Light source bulb for head lamp

Abstract

In first to third support wires ( 12, 13, 14 ) connected to a low beam filament L and a high beam filament H, which are arranged in the light source bulb 9, a bent portion 13 a is formed by bending the second support wire 13 from a curved portion 13 c towards the first support wire at an obtuse angle θ 2, and each rear lead Lb, Hb of the low beam filament L and the high beam filament H is connected to the bent portion 13 a. Moreover, a bent portion 14 a is provided by bending the third support wire 14 from a curved portion 14 c towards the second support wire at an obtuse angle θ 3, and a front lead Ha of the high beam filament H is connected to the bent portion 14 a. The extended portions 13 b and 14 b of the second support wire 13 and the third support wire 14 are inclined at an obtuse angle θ 4, θ5, respectively.

What is claimed is:  
     
       1. A light source bulb for a head lamp comprising: 
       a reflector;  
       a glass bulb attachable and detachable to/from the reflector;  
       a low beam filament having a filament axis below a central axis of the glass bulb, and a front lead and a rear lead;  
       a high beam filament having a filament axis at the obliquely lower side of the filament axis of the low beam filament, and a front lead and a rear lead;  
       first, second and third support wires connected to the low beam filament or high beam filament; and  
       a bridge for securing the first, second and third support wires; wherein,  
       the first, second and third support wires having an extended portion extending from the bridge into the glass bulb, respectively, and arranged at positions having different vertical relations with each other, the front lead of the low beam filament being connected to a front edge of the first support wire located at a high position, the rear lead of the low beam filament and the rear lead of the high beam filament being connected to a front edge of the second support wire located at a central position, respectively, and the front lead of the high beam filament being connected to a front edge of the third support wire located at a low position,  
       and wherein from a curved portion of the second support wire on the extended portion thereof extending from the bridge, a bent portion bent towards the first support wire is formed, an angle between the bent portion and the extended portion of the second support wire is an obtuse angle, and the rear lead of the low beam filament and the rear lead of the high beam filament are connected to the bent portion.  
     
     
       2. The light source bulb for a head lamp of  claim 1 , wherein a first distance between the extended portion of the second support wire and the extended portion of the third support wire at the bridge is shorter than a second distance of the extended portion of the second support wire and the extended portion of the first support wire at the bridge. 
     
     
       3. The light source bulb for a head lamp of  claim 1 , wherein an angle between the extended portion of the second support wire extending from the bridge into the glass bulb and the bridge is an obtuse angle, and the extended portion of the second support wire extending from the bridge into the glass bulb is inclined towards the third support wire. 
     
     
       4. The light source bulb for a head lamp of  claim 1 , wherein the third support wire forms a bent portion forming an obtuse angle towards the second support wire from a curved portion thereof on the extended portion extending from the bridge, and the front lead of the high beam filament is connected to the bent portion of the third support wire. 
     
     
       5. The light source bulb for a head lamp of  claim 4 , wherein the extended portion of the third support wire extending from the bridge into the glass bulb is inclined at an obtuse angle in the opposite direction to the second support wire. 
     
     
       6. The light source bulb for a head lamp of  claim 4 , wherein the bent portion of the third support wire is formed so as to have a curved surface. 
     
     
       7. The light source bulb of  claim 3 , wherein the rear lead of the high beam filament and the bent portion of the second support wire are connected with the shortest distance.